A light scanning apparatus that scans a scanned face with a light beam includes an adjusting unit that adjusts the position of a light spot of the light beam formed on the scanned face, and a compensating unit that compensates the light intensity of the light beam at the scanned face due to change caused by the adjustment of the position of the light spot. Accordingly, the light scanning apparatus can reduce or eliminate the deviation in exposure between scan lines of the multi-beam scan method and the deviation in exposure between photosensitive bodies of the tandem type image forming apparatus.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A light scanning apparatus configured to scan a scanned face with a light beam, comprising: a liquid crystal element configured to deflect the light beam to adjust the position of a light spot of said light beam formed on the scanned face, said liquid crystal element being provided between a light source and a polygon mirror; and a compensating unit configured to compensate a light intensity of the light beam at the scanned face due to a change caused by an adjustment of a position of the light spot, wherein said light scanning apparatus scans said scanned face with a plurality of N light beams emitted by N light sources, and said liquid crystal element further comprises at least N-1 deflecting units located between said light source and said polygon mirror, wherein each of the deflecting units deflects a corresponding one of the plurality of light beams in sub-scan directions and adjusts scan line pitch.
2. The light scanning apparatus as claimed in claim 1 , wherein said liquid crystal element further comprises a liquid crystal deflecting element.
3. The light scanning apparatus as claimed in claim 1 , wherein said deflecting unit further comprises a semiconductor laser and a coupling lens combined with a holder rotatable around an axis parallel to the optical axis of said coupling lens, the emission source of said semiconductor laser being eccentric to said optical axis.
4. The light scanning apparatus as claimed in claim 3 , wherein said deflecting unit further comprises an aperture combined with said holder configured to shape said light beam, said aperture being eccentric to the light path of said light beam emitted by said semiconductor laser and passing through the center of said coupling lens.
5. The light scanning apparatus as claimed in claim 1 , further comprising a detecting unit configured to detect the intensity of said light beam.
6. The light scanning apparatus as claimed in claim 1 , wherein said compensating unit is configured to control the radiation intensity of said light source.
7. The light scanning apparatus as claimed in claim 1 , further comprising a resin lens provided in the optical path from said light source to said scanned face.
8. A light scanning apparatus configured to scan a scanned face with a light beam, comprising: a liquid crystal element configured to deflect the light beam to adjust the position of a light spot of said light beam formed on the scanned face, said liquid crystal element being provided between a light source and a polygon mirror; and a compensating unit configured to compensate a light intensity of the light beam at the scanned face due to a change caused by an adjustment of a position of the light spot, wherein said liquid crystal element further comprises a second liquid crystal deflecting element array having a plurality of liquid crystal deflecting elements arrayed in main-scan direction, each of which is configured to deflect said light beam in sub-scan direction, said second liquid crystal deflecting element array being provided between said polygon mirror and said scanned face.
9. A light scanning apparatus configured to scan a scanned face with a light beam, comprising: a liquid crystal element configured to deflect the light beam to adjust the position of a light spot of said light beam formed on the scanned face, said liquid crystal element being provided between a light source and a polygon mirror; a compensating unit configured to compensate a light intensity of the light beam at the scanned face due to a change caused by an adjustment of a position of the light spot; and a detecting unit configured to detect the intensity of said light beam, wherein said detecting unit is further configured to detect said light beam for synchronization of light scanning.
10. A light scanning apparatus configured to scan a scanned face with a light beam, comprising: a liquid crystal element configured to deflect the light beam to adjust the position of a light spot of said light beam formed on the scanned face, said liquid crystal element being provided between a light source and a polygon mirror; a compensating unit configured to compensate a light intensity of the light beam at the scanned face due to a change caused by an adjustment of a position of the light spot; and an aperture provided between said light source and said polygon mirror and configured to shape said light beam, wherein said compensating unit is configured to displace said aperture.
11. An image forming apparatus, comprising: a photosensitive medium; and a light scanning apparatus configured to scan a scanned face of said photosensitive medium with a light beam, said light scanning apparatus further comprising: a liquid crystal element configured to deflect the light beam to adjust the position of a light spot of said light beam formed on said photosensitive medium, said liquid crystal element being provided between a light source and a polygon mirror; and a compensating unit configured to compensate the light intensity of the light beam at the photosensitive medium due to a change caused by the adjustment of said position of the light spot, wherein said light scanning apparatus scans said scanned face with a plurality of N light beams emitted by N light sources, and said liquid crystal element further comprises at least N-1 deflecting units located between said light source and said polygon mirror, wherein each of the deflecting units deflects a corresponding one of the plurality of light beams in sub-scan directions and adjusts scan line pitch.
12. The image forming apparatus as claimed in claim 11 , wherein said photosensitive medium is a photoconductive photosensitive body, and an electrostatic latent image formed by the light scanning is made visible by being converted into a toner image.
13. The image forming apparatus as claimed in claim 11 , wherein said image forming apparatus is a tandem type in which one or more photosensitive bodies that are drum-shaped or belt-shaped are provided along the path of a toner image medium, and a toner image formed on each photosensitive body is transferred to said toner image medium generating a composite color image.
14. The image forming apparatus as claimed in claim 13 , wherein four photosensitive bodies are provided corresponding to magenta, cyan, yellow, and black, or three photosensitive bodies are provided corresponding to red, green, and blue.
15. An image forming apparatus, comprising: a photosensitive medium; and a light scanning apparatus configured to scan said photosensitive medium with a light beam, said light scanning apparatus further comprising: a liquid crystal element configured to deflect the light beam to adjust the position of a light spot of said light beam formed on said photosensitive medium, said liquid crystal element being provided between a light source and a polygon mirror; and a compensating unit configured to compensate the light intensity of the light beam at the photosensitive medium due to a change caused by the adjustment of said position of the light spot, wherein said photosensitive medium is a photoconductive photosensitive body, an electrostatic latent image formed by the light scanning is made visible by being converted into a toner image, said light scanning apparatus is configured to scan said photoconductive photosensitive body with a plurality of N light beams emitted by N light sources, and said liquid crystal element further comprises at least N-1deflecting units located between said light source and said polygon mirror, each of the deflecting units being configured to deflect a corresponding one of the plurality of light beams in a sub-scan direction and to adjust a scan line pitch.
16. A light scanning apparatus, comprising: a liquid crystal element configured to deflect a light beam from a light source to adjust the position of a light spot formed by said light beam on a scanned face, wherein the ratio of a change in transmissivity (%) of said liquid crystal element caused by the deflection to a deflecting angle (minute) is equal to or smaller than 2.0 (%/minute).
17. The light scanning apparatus as claimed in claim 16 , wherein said ratio is equal to or smaller than 2.0 (%/minute) in 10 or more ranges of said deflecting angle, said ranges appearing cyclically.
18. The light scanning apparatus as claimed in claim 16 , further comprising: a detecting unit configured to detect the intensity of said light beam on said scanned face.
19. The light scanning apparatus as claimed in claim 16 , further comprising a compensating unit configured to compensate the intensity of said light beam on said scanned face.
20. An image forming apparatus, comprising: a scanned face; and a light scanning apparatus configured to scan said scanned face with a light beam and to form an electrostatic latent image on said scanned face, wherein said light scanning apparatus further comprises: a liquid crystal element configured to deflect said light beam from a light source to adjust the position of a light spot formed by said light beam on said scanned face, wherein the ratio of a change in transmissivity (%) of said liquid crystal element caused by the deflection to a deflecting angle (minute) is equal to or smaller than 2.0 (%/minute).
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
July 11, 2003
December 5, 2006
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